iirc its the mode sensor. and its on the transfercase.

 

another way to see if its in 4wd, is on a straight road and engage 4wd, and try to turn onto another street, if it resists to move whel you turned the wheel.. your in 4wd... thats the simple way to tell at least...

 

Hi guys,
I just purchased a 97 Dakota sport, 3.9L v6 4x4 (West Virginia reclemation project). I discovered the drive shaft extension housing is completely gone. My question is this, will that housing being gone - and therefore lack of fluid prevent the 4x4 from engaging? I can shift it into 4low and 4Hi and it feels like it goes in, I even noticed the poor tracking on dry pavement mentioned earlier. However when I got on some soft ground in my yard (picking up some firewood) only the rear wheels had power. And now I'm stuck. I've ordered the extension housing and I'm not driving the truck on the road until I get it fixed. Any thoughts? I think I've got the A231 transmission if that makes any difference (automatic) Thanks for any help.